Device for stabilization of an oscillating mass

ABSTRACT

An arrangement for stabilizing an oscillating mass, such as a gun or an optical or electronic instrument, mounted with two degrees of freedom on a moving frame, comprises means for transmission of torque to the oscillating mass, constituted by very low viscosity torque producing drive or torque motors with very slight viscosity mounted in direct engagement with the oscillating mass, and means for automatic correction of either systemic or arbitrary or random imbalances, constituted by a device for transfer of mass mounted directly on the assembly that is to be stabilized. In a preferred embodiment, the oscillating mass is a gun pivoted about a horizontal axis passing through or close to the center of gravity, having at one of its ends a metallic sector constituting the rotor of a stabilizing torque producer whose stator is integral with the gun turret and constitutes the inductor or field winding of the torque producer or motor. The mass transfer device preferably comprises an arrangement for automatically transferring liquid between tanks mounted on the oscillating mass on both sides of the axis of oscillation.

Uite tates atent [191 Vogel [4 1 Dec. 17,1974

[ DEVICE FOR STABILIZATION OF AN OSCILLATING MASS [75] Inventor: .Iean-Luc Vogel, Meudon, France [73] Assignee: Republic of France as represented by the State Minister charged with National Defence, Delegation Ministerielle pour IArmement, Paris, France [22] Filed: July 9, 1973 [21] Appl. No.: 377,288

[58] Field of Search... 89/37 F, 37 H, 41 LE, 41 H, 89/41 CE; 74/522; 188/267; 318/612, 613, 614, 648, 649, 382

[56] References Cited UNITED STATES PATENTS 2.193.446 3/1940 Caulkins 89/37 F 2,391,965 1/1946 Hanna ct al. 89/41 CE Primary ExaminerStephen C. Bentley Attorney, Agent, or Firm-Larson, Taylor & Hinds [57] ABSTRACT An arrangement for stabilizing an oscillating mass, such as a gun or an optical or electronic instrument. mounted with two degrees of freedom on a moving frame, comprises means for transmission of torque to the oscillating mass, constituted by very low viscosity torque producing drive or torque motors with very slight viscosity mounted in direct engagement with the oscillating mass, and means for automatic correction of either systemic or arbitrary or random imbalances, constituted by a device for transfer of mass mounted directly on the assembly that is to be stabilized. In a preferred embodiment, the oscillating mass is a gun pivoted about a horizontal axis passing through or close to the center of gravity, having at one of its ends a metallic sector constituting the rotor of a stabilizing torque producer whose stator is integral with the gun turret and constitutes the inductor or field winding of the torque producer or motor. The mass transfer device preferably comprises an arrangement for automatically transferring liquid between tanks mounted on the oscillating mass on both sides of the axis of 0scillation.

4 Claims, 1 Drawing Figure DEVICE FOR STABILIZATION OF AN OSCILLATING MASS FIELD OF THE INVENTION The present invention relates to a device for stabilizing an oscillating mass, such as a weapon or an optical or electronic instrument mounted with two degrees of freedom on a moving frame.

BACKGROUND AND SUMMARY For stabilization of an oscillating mass mounted with two degrees of freedom on a moving frame, such as a weapon or an optical or electronic instrument mounted on a vehicle, it is known that this stabilization can be attained by powered movement, generally hydraulic. This powered movement is arranged so as to be operated, on the one hand, by the aiming or pointing bar and, on the other hand, controlled by one or more inertial organs. This arrangement thus differs from that of a non-stabilized aiming device only in the addition of a servo control comprising in general servo valves, and inertial organs such as gyroscopes or gyrometers. It has been found that this arrangement provides for only extremely modest performance, essentially for three reasons. Thus, the loop gain of the servo mechanism control is rigorously limited by the low intrinsic anchoring frequencies of the oscillating mass, because otherwise there will be instability. Application of motion is irreversible and, consequently, all inertial couples or torque induced by movements of the structure are transmitted to the assembly that is to be stabilized. Finally, there are imbalances in the system, due particularly to loading, which transform inertial forces in duced by movements of the structure into an inertial couple or torque.

The oscillating mass stabilizer arrangement of the invention is intended to surmount the foregoing limitations, leading to an advance in performance of substantial magnitude.

Generally in accordance with the invention, the arrangement comprises means for transmission of torque to the oscillating mass, constituted by very low viscosity torque producing drives, or torque motors with very slight viscosity, mounted in direct engagement on the oscillating mass, and means for automatic correction of either systemic or arbitrary or random imbalances, constituted by a mass transfer device mounted directly on the assembly that is to be stabilized. Thus, there is obtained, on the one hand, application of motion that is totally reversible, which makes the oscillating mass insensitive to the inertial torque or couple, and, on the other hand, an automatic correction of the imbalance, suppressing the effect of the inertial forces. The loop gain can be increased considerably because the limitations are due, in this case, to the intrinsic flexion or bending frequencies of the oscillating mass alone. Finally, the stabilization work that the motor arrangement must furnish is theoretically zero, and therefore the device can be modestly dimensioned.

Other characteristics and advantages of the invention will be better understood from the following description of an exemplary embodiment, with reference to the attached drawing, wherein:

The single FIGURE is a diagrammatic or schematic view of an embodiment of a device according to the invention, applied to a stabilizing mechanism for a turret mounted gun.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, a gun I is mounted on a turret (not shown) that pivots about an axis XX, selected to pass through as closely as possible through the center of gravity of the gun that constitutes the oscillating mass. Gun 1 has a cradle 3 that is integral with a metallic sector 2 constituting the rotor of a stabilizing torque producer or motor with very low viscosity, whose stator 4 is integral with the turret and comprises the inductor or field winding. Torque producer or motor 2, 4 is electrically piloted or driven by amplifier 6 disposed in control box 5.

Moreover, means for automatic correction of systemic and random imbalances comprises a device for transfer of mass, mounted directly on the unit to be stabilized. This mass transfer device is constituted by two tanks 7, 7a mounted on the gun, on both sides of axis XX Tanks 7, 7a contain a certain amount of liquid that constitutes a mass that can be transferred from one tank 7 or 7a to the other by action of a double acting pumping unit 8. The motor of pumping unit 8 is itself controlled by an amplifier 9.

This transfer automatically corrects the imbalance couple or torque of the oscillating mass. Amplifiers 6 and 9 which respectively control inductor 4 of the torque producer and pumping unit 8 are controlled by the difference applied at 10 between the velocity command signal transmitted by lead 11 and issuing from the aiming station 12 and the velocity signal of the gun transmitted by lead 13, measured by gyrometer I4 mounted on cradle 3 of the gun. However, it is to be noted that use of inertial pickups such as gyrometer 14 is not indispensible for for the functioning of the device.

The described device does not allow interlocking of the stabilizer assembly, manual aiming, or execution of rapid rally operations. It is, therefore, necessary to retain a standard gearing arrangement, though one that can be engaged.

There are thus two ways of aiming: a first, in which the torque producer or motor is not energized and the gear is engaged, and a second, in which the torque producer is active and the gear is disengaged.

In the single FIGURE, a standard gearing is shown that comprises a toothed wheel 15 meshing with a toothed sector 16, integral with cradle 3, the toothed wheel being rigidly connected to a shaft 19 which, by means of an electromagnetic clutch 17, can be connected to standard mechanisms 18 for manual aiming and rapid rallying.

In stabilized aiming, clutch 17 is in the released position as mentioned above.

Of course, various modifications of the device can be made by the specialist without going beyond the scope of the invention. The illustrated embodiment should be considered as exemplary of the invention.

By way of further explanation, the drive must be piloted by a power amplifier in a special way. This arrangement must allow simultaneously the command and the stabilizing of the oscillating mass. The command function is attained by causing a couple applied to the oscillating mass to correspond to the amplifier input. The stabilizer function is effected by making this couple independent of the angle that the oscillating mass makes with the moving frame, as well as of the speed, acceleration, etc. of this angle. Practically this is attained by use of an amplifier that is slaved in current, and a motor with high coefficient of electromotive couple and low coefficient of counter electromotive couple. It is in this sense that it is to be understood that the drive has a low viscosity.

1 claim:

1. In combination with an oscillating mass pivotally mounted with two degrees of freedom on a moving frame, a stabilization device comprising means for transmission of torque to the oscillating mass, said means comprising a metallic sector carried by said oscillating mass at one of its ends and constituting the rotor of a stabilizing torque producing drive with very low viscosity whose stator is integral with the frame and constitutes the inductor, and means for automatic correction of systemic and random imbalances comprising a mass transfer device mounted directly on the mass to be stabilized.

2. Apparatus as claimed in claim 1, wherein the oscillating mass comprises a gun pivotal about a horizontal axis passing as closely as possible through the center of gravity of the oscillating mass, the metallic sector constituting the rotor of the stabilizing torque producer being carried by said gun at one of its ends and the stator of said stabilizing torque producer being integral with the turret of said gun.

3. Apparatus as claimed in claim 2 wherein the mass transfer device comprises two tanks mounted on the gun, on respective sides of the axis of oscillation, enclosing a liquid constituting a mass that can be transferred from one tank to the other, and pump means for transferring said liquid from one tank to the other.

4. Apparatus as claimed in claim 3 wherein the inductor of the torque producer and the motor of the pumping unit are, respectively, controlled by two amplifiers, said amplifiers being controlled by the difference between a velocity command signal from an aiming station and a velocity signal of the oscillating mass measured by a gyrometer mounted on said oscillating mass. 

1. In combination with an oscillating mass pivotally mounted with two degrees of freedom on a moving frame, a stabilization device comprising means for transmission of torque to the oscillating mass, said means comprising a metallic sector carried by said oscillating mass at one of its ends and constituting the rotor of a stabilizing torque producing drive with very low viscosity whose stator is integral with the frame and constitutes the inductor, and means for automatic correction of systemic and random imbalances comprising a mass transfer device mounted directly on the mass to be stabilized.
 2. Apparatus as claimed in claim 1, wherein the oscillating mass comprises a gun pivotal about a horizontal axis passing as closely as possible through the center of gravity of the oscillating mass, the metallic sector constituting the rotor of the stabilizing torque producer being carried by said gun at one of its ends and the stator of said stabilizing torque producer being integral with the turret of said gun.
 3. Apparatus as claimed in claim 2 wherein the mass transfer device comprises two tanks mounted on the gun, on respective sides of the axis of oscillation, enclosing a liquid constituting a mass that can be transferred from one tank to the other, and pump means for transferring said liquid from one tank to the other.
 4. Apparatus as claimed in claim 3 wherein the inductor of the torque producer and the motor of the pumping unit are, respectively, controlled by two amplifiers, said amplifiers being controlled by the difference between a velocity command signal from an aiming station and a velocity signal of the oscillating mass measured by a gyrometer mounted on said oscillating mass. 